Bromelain (also known as bromelin) is a mixture of proteolytic (protein digesting) and milk-clotting enzymes derived from the pineapple plant. The highest concentrations of bromelain are found in the stem of the plant, while smaller amounts are present in the fresh fruit. Canned pineapple does not contain bromelain, as the enzymes are destroyed during processing. Bromelain is available as a dietary supplement, usually in tablet or capsule form. The potency of bromelain supplements is usually measured in gelatin digesting units (GDU) although milk clotting units (MCU) are sometimes used. One GDU is approximately equal to 1.6 MCU.
Dosage recommendations for bromelain vary with intended use and product potency. Label information for bromelain supplements generally includes an indication of enzyme activity as well as appropriate dosage recommendations. Although bromelain has very low toxicity, occasional side effects, including gastric disturbances and diarrhea, have been reported. Because bromelain may increase the activity of some drugs, such as anticoagulants and certain antibiotics, people taking prescription medications should consult a physician before taking bromelain supplements.